1. Field of the Invention
The present invention is generally related to skin care compositions, and more specifically to cosmeceuticals and medicaments for topical application, including a skin cream, comprising cell culture medium conditioned by foreskin-derived fibroblast cells grown in two-dimensional culture.
2. Background Information
Currently there is no cure for aging skin and treatments for aging and/or wrinkled skin are temporary and suffer from drawbacks and side effects. The loss of collagen and elastic proteins present in the dermal layers causes a breakdown of resiliency and skin thickness over time, which may result in fine lines and wrinkles. The most common surgical interventions available for treatment of facial wrinkles include face-lifts, laser surgery, skin peels, and injection therapies, such as BOTOX®. However, surgical methods may result in detrimental complications, are often painful, and must be repeated with time. Non-invasive remedies include topical formulations consisting of alpha/beta hydroxy, retinoic acids, argirelines, and vitamins. However, none of these methods completely eliminate wrinkles, and require multiple, and often expensive treatments. Some topical formulations may act as irritants to the skin, to elicit wound healing responses, but do not successfully replenish the thinning skin with adequate proteins for treatment and/or prevention of age-related defects.
The pathogenesis of skin aging is well defined; it is characterized by a decrease in collagen synthesis and an increase in collagen breakdown, mediated by metalloproteinases (Arch. Dermatol. 138[11]:1462-70, 2002). This net loss in dermal collagen is believed to contribute to and/or permit wrinkling. Biologic factors that stimulate collagen production in wound healing might provide benefits for aging skin. Accordingly, growth factors, peptide fragments, and other biologically active molecules are being incorporated into anti-aging cosmeceuticals.
Growth factors are typically peptides with diverse biological effects. Some growth factor families that have been identified as useful in wound healing and/or epidermal remodeling include, e.g., transforming growth factor-β (TGF-β), epidermal growth factor (EGF), insulin-like growth factors (IGFs), platelet-derived growth factor (PDGF), and fibroblast growth factors (FGFs).
Living cells cultured in vitro secrete extracellular proteins and peptides, including growth factors, into the nutrient medium in which they are cultured. Medium exposed to cells in culture is referred to as “conditioned medium.” Naughton et al., in U.S. Pat. No. 6,372,494, teach that conditioned medium from cell cultures comprising a three-dimensional extracellular matrix and multiple layers of stromal and tissue specific cells (i.e., a three-dimensional culture system) may be used advantageously to prepare growth factor-enriched cosmeceutical compositions; U.S. Pat. No. 6,372,494 is herein incorporated in its entirety by reference thereto. Indeed, Naughton et al. assert that the complex three-dimensional culture systems have numerous advantages over simple two-dimensional culture systems, e.g., greater surface area; more analogous to tissues in vivo; absence of “contact inhibition” (a limitation on the growth of cells in two-dimensional cultures); creation of localized microenvironments; increased cell-cell interactions and potential cell migration; maintenance of a differentiated phenotype and elaboration of differentiation factors, etc. Unfortunately, three-dimensional culture systems are substantially more expensive and technically challenging to establish and maintain than conventional two-dimensional culture systems. Moreover, the complex biological systems formed in three-dimensional culture create so many variables (e.g., cell-cell and cell-matrix interactions, tissue differentiation, etc.), that quality control with respect to the harvested conditioned medium becomes nearly impossible, and batch-to-batch variability in growth factor composition may be commercially unacceptable.
Accordingly, while the use of growth factors to treat aging skin is gaining favor among skin care professionals, there remains an important and unmet need for more effective topical formulations for the treatment and/or prevention of skin damage, wrinkles and/or other defects due to aging and environmental factors, where the formulations comprise conditioned medium enriched with growth factors and/or extracellular matrix compositions produced by economical, well-controlled and uniform two-dimensional cell culture methods.